Foldable pallet-mounted containers are used for shipping a variety of goods such as bulk material in aggregate, fibrous or powdery form, food in bags or pouches, commodities packed in small boxes and loose components used in assembly lines. Paperboard pallets and containers are generally preferred by the environment-conscious users, because this material is entirely recyclable. Corrugated paperboard material, however, is not as durable as wood, composite materials or metal, and the design of a container made with it requires additional ingenuity to ensure that the useful life of the container will be comparable or superior to the duration of those made with the conventional materials.
A first example of a foldable pallet-mounted container of the prior art is illustrated and described in U.S. Pat. No. 4,383,609 issued on May 17, 1983 to Eugene C. Lochmiller. The container of this invention comprises a corrugated cardboard base which is built into a wooden pallet, and a rectangular corrugated cardboard sleeve which is adapted to slide over the base and to vertically interlock with the base. A cover member fits over the rectangular sleeve to form with the sleeve and the base, a closed container integrally mounted to a wooden pallet.
In a second example of a foldable container of the prior art, U.S. Pat. No. 4,927,026 issued on May 22, 1990 to Haas K. Gossler and Charles P. Roberts, discloses a corrugated cardboard box affixed to a wooden pallet. The box is made of two parts. The first part comprises a floor and four vertically extending flaps. The second part is a rectangular tubular member that fits over the four flaps, thereby forming a double layered container.
Another type of collapsible corrugated board container is described in U.S. Pat. No. 5,318,219 issued on Jun. 7, 1994 to Glenn M. Smith. In this invention, an integral corrugated cardboard box is stapled to a pallet and is foldable in a compact flat form. The bottom portion of the box is foldable over itself to allow opposite sides of the box to lay parallel over top of one another.
A further example of a foldable container is described in U.S. Pat. No. 5,441,154 issued on Aug. 15, 1995 to Donald R. Youell, III. The paperboard container and pallet system described therein comprises a shallow deck portion mounted on hollow cardboard runners, a wall-forming portion and a cover. The wall-forming portion has locking tabs on its lower edge, and these tabs are adapted to lock into matching slots through the deck portion and the hollow runners. Notches are provided in the hollow runners for selectively releasing the locking tabs from the deck portion and refolding the wall-forming portion of the container into the deck portion.
It is believed that a first preferred requirement by the industry regarding foldable pallet-mounted containers is that the wall forming portion should be an integral part of the base portion such that the box portion is inseparable from the base portion throughout the life of the container. A second preferred requirement by the industry is believed to be that the container should be foldable without having to manipulate the pallet, or otherwise reach under the pallet and into intricate cavities to undo locking tabs. Similarly, it is believed that a third preferred requirement by the industry is that the deployed container has sufficient strength for resisting lateral internal pressure associated with a loading thereof with heavy granular material for example. Finally, another preferred requirement by the industry is believed to be that the corrugated board container is securely foldable to avoid damages during transport back to the original filler.
The foldable containers of the prior art are believed to be deficient at least one of the above preferred requirements, and it is this reason basically that has contributed to the development of a market demand for better foldable containers capable of resisting the loading of a variety of products and in particular, that can be used for a relatively large number of shipping-returning cycles.